The ion tail of C/2023 A3 (Tsuchinshan-ATLAS) could appear as a blue streak across the northern hemisphere sky during October, in a rare event thought to happen only every few decades The ion tail of C/2023 A3 (Tsuchinshan-ATLAS) could appear as a blue streak across the northern hemisphere sky during October, in a rare event thought to happen only every few decades New Scientist – News